Sunday, August 30, 2015

Situated music - a theory of musical affordance

Clancey describes situated cognition as a correction to the naive ideas of artificial intelligence. I think that there is a parallel between the idea of embedded music and abstract music, the former being a product of the musical affordance of an instrument, the latter the idea of universal unembodied melody - glassperlenspeil if you like. It comes from an idea of Hugh Tracey's in his book for an African music, Ngoma.

I have been constructing a series of hybrid instruments as a means of exploring the doctrine of (for want of a better phrase, I have called) instrumental affordance. This is the idea of the interplay between the layout of an instrument and the kinds of music that develops for it.

 This idea was proposed formally by the musicologist Hugh Tracey in his book Ngoma (1948), but has been sort of mentioned elsewhere. It's particularly obvious with thumb pianos, wherein there are missing notes or notes that are present twice or even three times to make certain things easily played.
 The Effects of Instruments upon Music
Although we make musical instruments to play our music as we want it, we sometimes find that the instrument plays its own music—notes that we did not expect. It is like driving a donkey along a path. So long as the donkey stays on the path it is our way; but sometimes it refuses to go along the path and goes off into the grass to find its own way. Every musician well knows what this means. The instrument in his hands seems to come alive, and without his knowing quite what is happening he plays sequences of notes which do not come from his mind but from his fingers on the instrument. Then if this new sequence sounds well he may try to fix it in his mind and play it again. So the instrument itself has added something to the music, more than was thought out in the mind of the composer alone.

A great number of musical phrases come from the instruments in this way. The bows make certain harmonics which we use as yodels (maguri); the position of the keys of the Mbira makes it easier to play certain sequences of notes which, maybe, lie close to each other; the flutes produce an unexpected number of small notes if we blow harder, and we have to accept the notes that they make because they can make no others.

The music of any instrument or voice shows clearly the features (the likeness) of its parents. For instance, when we sing we can hold on to one note for a long time. But not so on the Mbira. We must keep on striking it to keep the note sounding. Some, musicians put extra notes on the Mbira for this purpose, notes of the same pitch on either side, so that they can make one note sound a long time by playing it with two thumbs alternately. So where we can sing one long note, the Mbira would have to play several beats :
Voice : Nde-------------------------------------------
Mbira: Da-ka-da-ka-da-ka-da-ka-da-ka-da-ka-da-ka
The characteristics of each instrument and its manner of playing can thus be turned to good account by clever musicians.

In the course of a great number of years, the constant use of one kind of instrument has a deep and lasting effect upon the music of the people who use it. The manner of playing instruments is also most important. For example, the drums which are played with the palms of the hands make quite a different sound from those played with beaters. The quick vibrations of a light beater on a tight drum head (kettledrums) are much used by European military bands, but you rarely hear this sound from our drums. But on the other hand they cannot achieve so great a variety of blows as we do on our drums.

Each instrument that we use helps to make up the character of our music. If we changed our instruments our music would also change. Centuries of work and skill would be lost if we ceased to play our own instruments. The music of the Mbira, for instance, if played on a European piano would soon lose all the special character which is part of its charm.

The notion of  instrumental affordance is based on J J Gibson's theory of affordances -
"The affordances of the environment are what it offers the animal, what it provides or furnishes, either for good or ill." 
So instrumental affordances are the obvious possibilities what a musical instrument offers the performer and/or composer for good or ill (inspiration or cliche). Gibson's categories of affordances include those
"of the medium, of substances, of surfaces and their layout, of objects".
 (Gibson 1979). I'll put more at the bottom of this blog

Back to Tracey - he points out that the instrument evolves to meet the increased needs of the musician, who then sees new possibilities in each newly evolved instrument, and so it goes. we can see that there are affordances of medium, substance, surface and surface layout for an instrument. The medium is common between all instruments - sound travelling through air. The substance gives the nature of the instrument - these are the Sachs categories of idiophones, aerophones, chordophones. For a musical instrument this can be termed a sonoral affordance.

Each instrument also presents a surface to the musician (again, musician here includes performer, composer, arranger, transcriber, builder and designer). So the difference in surface and surface layout between (say) a fife and a piccolo is the keying and all that enables. This is different to the object affordance that is the difference between a piccolo and an alto flute, but have the same surface layout. A common substance and surface layout give a working definition of a family of instruments. We can call this the melodic affordance.

Seen backwards, we can look at this as the musical umwelt (per von Uexkull, Fraser) of the musician - their musical universe is observed through this instrumental affordance. So the possibilities that are possible are relatively unlimited, but there is a large preponderance of things that are obviously beautiful or emotionally charged.

Since this is an observable phenomenon, it seemed to me that (following the idea of conceptual blending of per Fauconnier) new musical umwelts would be possible by mixing the substance of one family with the surface layout of another family. So I set about making instruments that presented these hypothesised new musical umwelts to me, while making them eminently playable.

I have been building as a series of experiments hybrid kalimbas, using the melodic affordances of other  instruments with the sonoral affordance of the kalimba. I have then arranged the traditional material of the instrument providing the melodic affordance, then improvised to see what follows. When the "experiment" is "complete", I'll write up what I learned, but my expectations were exceeded in  ways that would sound like exaggeration.

Here's a brief survey. 

 The Tonkori Kalimba 

This instrument (built for me by Darko Korocek of Instruments Korocek) combines the 5-note re-entrant tuning of the Ainu Tonkori fretless zither. It has two ranks so the notes can be played as parallel octaves (in the way that a twelve string guitar sounds jangly)  .
I arranged the repertoire of the tonkori for it, then explored the instruments affordance to see what tunes emerged from given starting points


The marovany kalimba

 This instrument combines the affordance of the marovany (a box harp from Madagascar) with the tines of the kalimba (it has been done by other people as well, I'll find the link when I get a chance). It was built for me by Ray Vincent of Ray's Rootworks:
It's played from a strap around the neck:

 The other two are ongoing - the pocket gamelan and swarkalimba


This instrument combines the affordance of the swarsangam with the kalimba.

This affordance is a tampura bass, with a swarmandel arangement.It was made for me by the Caleb Schepart at NyKalimba.

I have yet to make a "proper" recording of it, this is me fiddling with it the day it arrived

Pocket Gamelan

There are two pocket gamelans and they require very large pockets: they were made for me by William Harper - one is in pelog

and the other in slendro

Here is a pelog extemporisation

more to come on these.


The affordances of the environment are what it offers the animal, what it provides or furnishes, either for good or ill. The verb to afford is found in the dictionary, but the noun affordance is not. I have made it up. I mean by it something that refers to both the environment and the animal in a way that no existing term does. It implies the complementarity of the animal and the environment. The antecedents of the term and the history of the concept will be treated later; for the present, let us consider examples of an affordance....

If a terrestrial surface is nearly horizontal (instead of slanted), nearly flat (instead of convex or concave), and sufficiently extended (relative to the size of the animal) and if its substance is rigid (relative to the weight of the animal), then the surface affords support....

Note that the four properties listed --- horizontal, flat, extended, and rigid --- would be physical properties of a surface if they were measured with the scales and standard units used in physics. As an affordance of support for a species of animal, however, they have to be measured relative to the animal. They are unique for that animal. They are not just abstract physical properties....
An elongated object of moderate size and weight affords wielding. If used to hit or strike, it is a club or hammer. If used by a chimpanzee behind bars to pull in a banana beyond its reach, it is a sort of rake. In either case, it is an extension of the arm. A rigid staff also affords leverage and that use is a lever. A pointed elongated object affords piercing -- if large it is a spear, if small a needle or awl.

As adapted by Norman: (Psychology of Everyday Things)
The term affordance refers to the perceived and actual properties of the thing, primarily those fundamental properties that determine just how the thing could possible be used. A chair affords (‘is for’) support and, therefore, affords sitting. A chair can also be carried

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